title: Local cooling reduces regional bone blood flow.
abstract: Local cooling is very common after bone and joint surgery. Therefore the knowledge of bone blood flow during local cooling is of substantial interest. Previous studies revealed that hypothermia leads to vasoconstriction followed by decreased blood flow levels. The aim of this study was to characterize if local cooling is capable of inducing reduced blood flow in bone tissue using a stepwise-reduced temperature protocol in experimental rabbits. To examine bone blood flow we utilized the fluorescent microsphere (FM) method. In New Zealand white rabbits one randomly chosen hind limb was cooled stepwise from 32 to 2°C, whereas the contra lateral hind limb served as control. Injection of microspheres was performed after stabilization of bone and muscle temperature at each temperature level. Bones were removed, dissected and fluorescence intensity was determined to calculate blood flow values. We found that blood flow of all cooled regions decreased relative to the applied external temperature. At maximum cooling blood flow was almost completely disrupted, indicating local cooling as powerful regulatory mechanism for regional bone blood flow (RBBF). Postoperative cooling therefore may lead to strongly decreased bone blood flow values. As a result external cooling has capacity to both diminish bone healing and reduce bleeding complications.
authors.affiliation: Department of Trauma Surgery, Technical University of Munich, Klinikum rechts der Isar, Ismaninger Straße 22, 81675, Munich, Germany; Department of Orthopaedic Sports Medicine, Technical University of Munich, Klinikum rechts der Isar, Ismaninger Straße 22, 81675, Munich, Germany.
authors.forename: Arne J
authors.initials: AJ
authors.lastname: Venjakob
authors.forename: Stephan
authors.initials: S
authors.lastname: Vogt
authors.forename: Klaus
authors.initials: K
authors.lastname: Stöckl
authors.forename: Thomas
authors.initials: T
authors.lastname: Tischer
authors.forename: Philipp J
authors.initials: PJ
authors.lastname: Jost
authors.forename: Eckart
authors.initials: E
authors.lastname: Thein
authors.forename: Andreas B
authors.initials: AB
authors.lastname: Imhoff
authors.forename: Hermann
authors.initials: H
authors.lastname: Anetzberger
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000098:blood supply*; D003080:Cold Temperature; D005260:Female; D005269:Femur / Q000098:blood supply; D011817:Rabbits; D012039:Regional Blood Flow / Q000502:physiology*; D013977:Tibia / Q000098:blood supply; D014655:Vascular Resistance
keywords: bone blood flow; local cooling; microspheres